| May 31, 2013 | May 31, 2012 | |||||
| Costs incurred on uncompleted contracts | 2,822,541 | 9,669,917 | ||||
| Estimated earnings | 653,458 | 2,361,081 | ||||
| Total costs and estimated earnings | 3,475,999 | 12,030,998 | ||||
| Less billings to date | 1,190,058 | 7,207,870 | ||||
| Costs and estimated earnings not billed | 2,285,941 | 4,823,128 | ||||